1. Field of the Invention
The present invention relates to an inkjet recording apparatus and a printing method. In particular, the present invention relates to an inkjet recording apparatus which may be an image forming apparatus such as a copier, a printer, a facsimile machine, a digital multifunction peripheral having these functions in a combined manner or a printing machine forming (printing) an image according to an inkjet method on a sheet-shaped recording medium such as paper or the like, cloth or the like, film or the like, or a synthetic resin material wound on a roll, and a printing method carried out in the inkjet recording apparatus.
2. Description of the Related Art
In an inkjet recording apparatus, ink droplets are discharged onto a sheet-shaped recording medium by an inkjet head, the ink droplets are caused to penetrate into the sheet-shaped recording medium or are caused to adhere to a surface of the sheet-shaped recording medium so that an image is formed or printed on the sheet-shaped recording medium. Since ink droplets are used, as an atmosphere of a printing area comes to have a high humidity environment, and not only the printing area of the sheet-shaped recording medium at which printing is carried out but also the sheet-shaped recording medium itself may become moist.
On the other hand, in an inkjet recording apparatus carrying out high-speed printing, in many cases, a continuous sheet of paper (sheet of paper), wound to be like a roll, is drawn out from the roll, printing is carried out thereon, and after that, the continuous sheet of paper is again wound to be like a roll. Therefore, it is necessary to dry the continuous sheet of paper before being wound. Otherwise, staining, blurring, ink running, or such may occur due to adhesion of the printed ink, or trouble may occur during winding the continuous sheet of paper.
Therefore, Japanese Laid-Open Patent Application No. 2002-361850 (Patent Document 1) discloses providing a hot air machine that generates hot air; a drying body in which a continuous sheet of paper is dried; and a dehumidification machine that dehumidifies the hot air. Then, the hot air generated by the hot air machine is led to the drying body, the continuous sheet of paper is thus dried, the hot air led to the drying body is led to the dehumidification machine and is dehumidified, and the dehumidified hot air is again led to the drying body.
Japanese Laid-Open Patent Application No. 2010-83040 (Patent Document 2) discloses providing a drying part including a main drying section for drying cloth on which recording has been carried out by an inkjet recording part; auxiliary drying sections disposed to sandwich the main drying section; and a conveyance part for conveying the cloth. The auxiliary drying sections are set to have an atmosphere of a normal temperature and low humidity by using a dehumidification machine. In the main drying section, the air in the inside is circulated by an air flow generator and is fed to a surface of the cloth, and thus, the cloth is dried.
According to the related art of Patent Document 1, the continuous sheet of paper is dried by the hot air. According to the related art of Patent Document 2, the cloth is dried in the normal temperature. In each case, the air used in the drying process is dehumidified, and is again used for the drying process.
According to the related art of Patent Document 1, the hot air is fed to a housing, the continuous sheet of paper is caused to pass through the housing, and the continuous sheet of paper is dried. However, improving the drying efficiency by reducing the power consumption or such is not particularly considered there. Further, it may be difficult to apply this method to a high-speed inkjet recording apparatus. According to the related art of Patent Document 2, a space in the inside of the drying part is maintained to have a normal temperature (25 through 50° C.) and low humidity (0 through 20%), and the cloth is caused to pass through the space during a time period on the order of 1 through 5 minutes for drying the cloth. However, since the cloth is to be caused to pass through the space during the time period on the order of 1 through 5 minutes, it may be difficult to apply this method to a high-speed inkjet recording apparatus.
Thus, according to the related art of Patent Documents 1 and 2, if an inkjet head is used to carry out printing at a high speed, the speed of drying the printed sheet may not catch up with the printing speed, and thus, the upper limit of the printing speed may depend on the time period required for the drying process. Further, when the temperature is increased in order to improve the drying efficiency, the power consumption may be increased accordingly. Further, an areal deviation may occur in drying the sheet of paper, and thereby, the printing quality may be degraded.